Extrusion molding apparatus for product having wood pattern and extrusion molding method thereof

ABSTRACT

An extrusion molding apparatus for a product having a wood pattern and an extrusion molding method are disclosed, in which a second synthetic resin containing a wood powder of 80˜120 meshes at a predetermined ratio is fed to a die through a second extruder and then is coated on a surface of the product, thereby providing an esthetic surface and an improved durability. The extrusion molding apparatus is designed to successively produce a product having a wood pattern with a predetermined sectional shape by feeding a thermoplastic synthetic resin to an extruder and extruding the product through a die installed at an outlet of the extruder, wherein a second inlet is formed at one side of the die to fit a second synthetic resin thereinto, a second extruder which feeds the second synthetic resin is connected to the second inlet, and a second passage communicated with the second inlet of the die is formed to communicate with an original synthetic resin passage formed in the die, thereby coating the second synthetic resin on a surface of the product extruded from the die.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an extrusion molding apparatusand an extrusion molding method, and more particularly to an extrusionmolding apparatus for a product having a wood pattern and an extrusionmolding method thereof, in which a second synthetic resin containing awood powder of 80˜120 meshes at a predetermined ratio is fed to a diethrough a second extruder and then is coated on a surface of the productextruded from the die, thereby obtaining an esthetic surface andimproving durability.

[0003] 2. Discussion of the Related Art

[0004] Generally, extrusion molding is to successively manufactureproducts, such as pipes, rods, sheets, films, fibers, and coatingcables, by extruding a thermoplastic synthetic resin, which has beenheated and softened, from an extrusion die using an extruder.

[0005] A conventional extrusion molding apparatus is configured to windor cut the product by placing a pellet shaped thermoplastic syntheticresin in a hopper, softening it with a screw in a heating cylinder,extruding it from the die, and cooling it. The conventional extrusionmolding apparatus is characterized in that a softening resin issuccessively extruded with a screw. The products having various sectionsmay be made depending on shapes of holes of an extrusion die at anoutlet of an extruder. Such extrusion molding is widely used inaccordance with the development of polymer compounds such as syntheticresin and has become a basis of mass production.

[0006] Among the products based on the above-described extrusionmolding, there are the products having a constant section, such as awindow frame and a doorframe. These products are on a high-grade trendto give an effect of raw lumber. If the product is manufactured using ageneral synthetic resin, it is likely that the product having a singlecolor is manufactured. Therefore, the product coated with a film, suchas sheet with a wood pattern, wood, and paper, to give an effect of rawlumber is recently coming out in the market.

[0007] However, the product coated with such a film has severalproblems. Since the film is made of a material and characteristicsdifferent from those of the product, the film and the productrespectively have different shrinkage depending on temperature changes.In this case, a problem arises in that it is likely to take the film,such as sheet, wood, and paper, off the product as time passes.

SUMMARY OF THE INVENTION

[0008] Accordingly, the present invention is directed to an extrusionmolding apparatus for a product having a wood pattern and an extrusionmolding method that substantially obviates one or more of the problemsdue to limitations and disadvantages of the related art.

[0009] An object of the present invention is to provide an extrusionmolding apparatus for a product having a wood pattern and an extrusionmolding method, in which a second synthetic resin containing a woodpowder of 80˜120 meshes is coated on a surface of the product atdifferent ratios.

[0010] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be apparentfrom the description, or may be learned by practice of the invention.The objectives and other advantages of the invention will be realizedand attained by the scheme particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

[0011] To achieve these and other advantages and in accordance with thepurpose of the present invention, as embodied and broadly described, inan extrusion molding apparatus for successively producing a producthaving a wood pattern with a predetermined sectional shape by feeding athermoplastic synthetic resin to an extruder and extruding the productthrough a die installed at an outlet of the extruder, it ischaracterized in that a second inlet is formed at one side of the die tofit a second synthetic resin thereinto, a second extruder which feedsthe second synthetic resin is connected to the second inlet, and asecond passage communicated with the second inlet of the die is formedto communicate with an original synthetic resin passage formed in thedie, thereby coating the second synthetic resin on a surface of theproduct extruded from the die.

[0012] In another aspect of the present invention, an extrusion moldingmethod for successively producing a product having a wood pattern with apredetermined sectional shape by feeding a thermoplastic synthetic resinto an extruder and extruding the product through a die installed at anoutlet of the extruder, the extrusion molding method includes the stepsof: forming a second passage in a synthetic resin passage in the die tocommunicate with the synthetic resin passage; and connecting a secondextruder to the second passage so that the second synthetic resin iscoated on a surface of the product extruded from the die.

[0013] In other aspect of the present invention, in an extrusion moldingdie for a product having a wood pattern, provided with a thermoplasticsynthetic resin and a synthetic resin passage, the thermoplasticsynthetic resin being installed at an outlet of an extruder so that itis to be fed to the extruder and then extruded in the product having apredetermined sectional shape such as the synthetic resin passage, asecond inlet is formed at one side of the die to fed a second syntheticresin thereto, and the second inlet is formed to communicate with asecond passage communicated with the synthetic resin passage of the dieso that the second synthetic resin is coated on a surface of the productextruded from the die.

[0014] It is to be understood that both the foregoing generaldescription and the following detailed description are exemplary andexplanatory and are intended to provide further explanation of theinvention as claimed.

BRIEF DESCRIPTION OF THE ATTACHED DRAWINGS

[0015] The invention will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

[0016]FIG. 1 is a perspective view of a product manufactured by anextrusion molding method according to the present invention;

[0017]FIG. 2 is a perspective view of an extrusion molding apparatusaccording to the present invention;

[0018]FIG. 3 is a perspective view of a second extruder in an extrusionmolding apparatus according to the present invention;

[0019]FIG. 4 is a perspective view of an extrusion molding die accordingto the present invention;

[0020]FIG. 5 is a front view of a second molding member which is a partof the extrusion molding die according to the present invention;

[0021]FIG. 6 is a sectional view taken along line IV-IV of FIG. 3;

[0022]FIG. 7 is a front view of a first molding member which is a partof the extrusion molding die according to the present invention;

[0023]FIG. 8 is a sectional view taken along line VI-VI of FIG. 5;

[0024]FIG. 9 is a sectional view taken along middle portions of thefirst and second molding members, illustrating combination of FIG. 4 andFIG. 6; and

[0025]FIG. 10 is a front view of a first molding member which is a partof the extrusion molding die according to the present invention,illustrating a feeding state of a second synthetic resin.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Reference will now be made in detail to the preferred embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings.

[0027] An extrusion molding product 1 according to the presentinvention, as shown in FIG. 1, is configured such that an originalsynthetic resin is coated with a second synthetic resin lb. The secondsynthetic resin 1 b contains a wood powder of 80˜120 meshes and iscoated on a surface of the original synthetic resin at different ratiosso that a wood pattern la is formed.

[0028] As shown in FIGS. 2 to 4, an extrusion molding apparatus formanufacturing the aforementioned product 1 includes a first extruder100, a die 10 installed at an outlet of the first extruder 100, and asecond extruder 200 installed at a side of the die 10.

[0029] The first extruder 100 has the same configuration as that of ageneral extruder. That is, the first extruder 100 includes a heatcylinder 101 provided with a heater 102 on an outer surface, a hopper103 for supplying a first thermoplastic synthetic resin to an innerportion of the heat cylinder 101, a screw 104 for extruding the firstsynthetic resin softened by heat in the heat cylinder 101 to the die 10by rotation, and a driver 110 for driving the screw 104.

[0030] Likewise, the second extruder 200 has the same configuration asthat of a general extruder. The second extruder 200 includes a heatcylinder 201 provided with a heater 202, a hopper 203, a screw (notshown), and a driver 210. The hopper 203 is supplied with a secondsynthetic resin which contains a wood powder of 80˜120 meshes to form awood pattern 1 a on a surface of the product 1 to be extruded.

[0031] The die 10 connected with the first and second extruders 100 and200, as shown in FIGS. 4 to 10, includes first synthetic resin passages21 and 31 for extruding the first synthetic resin. The second extruder200 is connected between two moldings 20 and 30 coupled to each other atthe foremost among a plurality of moldings constituting the die 10. Thesecond synthetic resin is fed between the two moldings and then isextruded along a passage formed to communicate with the first syntheticresin passages 21 and 31. Since the second synthetic resin passage isextruded around the first synthetic resin passages 21 and 31 by theabove structure, the second synthetic resin is coated on the firstsynthetic resin passages 21 and 31 constituting the product 1. Since thesecond synthetic resin contains a wood power of 80˜120 meshes, a woodpattern 1 a is formed on a surface of the product 1.

[0032] The wood pattern 1 a is distinctly formed on the surface of theproduct 1 by the two moldings 20 and 30 at the end among the moldings ofthe die 10. That is, a connecting passage 40 is formed between thesecond molding member 20 at the end of the die 10 and the first moldingmember 30 next to the second molding member 20. The second syntheticresin containing a wood powder formed by grinding wood is fed to theconnecting passage 40. The connecting passage 40 is connected with thesecond extruder 200. The second synthetic resin which passed through theconnecting rod 40 moves to the synthetic resin passages 21 and 31 alonga passage formed inside the first and second molding members 20 and 30and is coated on the surface of the synthetic resin extruded by pressureof the first extruder.

[0033] The first molding member 30, as shown in FIGS. 4 to 6 and FIG. 9,includes half of the connecting passage 40 having a screw for connectingto the second extruder. The synthetic resin passage 31 is formed insidethe first molding member 30, and a slit surface 32 is formed around thesynthetic resin passage 31 at a height lower than a surface of the firstmolding member 30 so that the second synthetic resin flows to thesynthetic resin passage 31. A retainer groove 30 connected to theconnecting passage 40 is formed around the slit surface 32. The retainergroove 33 is lower then the slit surface 32. Therefore, after the secondsynthetic resin is completely filled in the retainer groove 33, itpasses through the slit surface 32 toward the synthetic resin passage 31by pressure of the second synthetic resin and then extruded through thewhole surface.

[0034] The second molding member 20, as shown in FIG. 4, and FIGS. 7 to9, is symmetrically formed to engage with the first molding member 30.Half of the connecting passage 40 having a screw for connecting with thesecond extruder is formed in the second molding member 20 so that thecomplete connecting passage 40 is formed together with the connectingpassage 40 formed in the first molding member 30. In the same manner asthe first molding member 30, the synthetic resin passage 21 is formed inthe second molding member 20. A lead surface 22 is formed around thesynthetic resin passage 21 together with the slit surface 32, therebyforming a space where the second synthetic resin flows. A retainergroove 23 connected to the retainer groove 33 of the first moldingmember 30 is formed around the lead surface 22. Particularly, the secondmolding member 20, as shown in FIGS. 7 to 9, includes a plurality ofnozzle grooves 24 formed with a curved section, which is higher than theretainer groove 23 but lower than the lead surface 22, between theretainer groove 23 and the synthetic resin passage 21. Each of thenozzle grooves 24 includes a distal end 24 a supplied with the secondsynthetic resin at a greater amount than that supplied to any otherportions, thereby forming a wood pattern. The distal end 24 a has asectional area smaller than that of any other portions to serve as anozzle. The nozzle grooves 24 are inclined at a predetermined anglealong an incoming direction of the second synthetic resin so that thesecond synthetic resin readily moves to the nozzle grooves 24 throughthe retainer groove 23.

[0035] The retainer grooves 23 and 33 of the first and second moldingmembers 20 and 30, as shown in FIG. 9, are formed to surround thesynthetic resin passages 21 and 31 and have a curved section with apredetermined gradient.

[0036]FIG. 9 is a sectional view illustrating a coupling state of thefirst and second molding members 20 and 30. As shown in FIG. 9, thesecond synthetic resin is introduced into the retainer grooves 23 and 33through the connecting passage 40 and then moves to the synthetic resinpassages 21 and 31 through the space between the slit surface 32 and thelead surface 22. Particularly, as shown in FIG. 7, since the portionwhere the nozzle grooves 24 are formed has a greater passage area thanany other portions, the second synthetic resin moves at a greateramount, thereby resulting in that a wood pattern 1 a is formed on thesurface of the product 1.

[0037] The operation of the aforementioned extrusion molding apparatuswill now be described based on the flow of the first and secondsynthetic resins.

[0038] First, the first synthetic resin, as shown in FIGS. 2 and 3, isfed to the first extruder 101 through the hopper 103 and moves to thedie 10 by pressure of the rotating screw 104. At this time, the firstsynthetic resin moves while being softened by the heater 102. The firstsynthetic resin moved to the die 10 by the screw 104 is extruded inaccordance with shapes of the first synthetic resin passages 21 and 31formed in the die 10, so that the product 1 is successively produced.

[0039] The aforementioned extrusion method is the same as the operationof the typical extrusion molding apparatus. In addition to the abovemethod, in the present invention, the second synthetic resin containinga wood powder of 80˜120 meshes, as shown in FIGS. 2 and 3, is fed to thesecond extruder 200 through the hopper 203 and moves through the screwand the second passage 40 formed at a side of the die 10 whilebeing-softened by the heater 202. The second synthetic resin introducedinto the side between the first and second molding members 20 and 30, asshown in FIG. 9, is introduced around the first synthetic resin passages21 and 31 through the space formed by the retainer grooves 23 and 33 ofthe first and second molding members 20 and 30. At this time, the secondsynthetic resin is also introduced into the space formed by the nozzlegrooves 24 and the slit surface 32. Afterwards, the second syntheticresin is fed to the distal end 24 a of the nozzle groove 24 and at thesame time moves to the surface of the first synthetic resin extrudedthrough the space formed by the slit surface 32 and the lead surface 22.Therefore, the first synthetic resin is coated with the second syntheticresin. At this time, since the second synthetic resin extruded throughthe nozzle grooves 24 has a greater amount, the wood pattern 1 a isformed on the surface of the product 1.

[0040] The operation of the first and second molding members 20 and 30will be described in more detail.

[0041] The second extruder is connected to the first and second moldingmembers 20 and 30 through the connecting passage 40 so that the secondsynthetic resin containing a wood powder is fed to the first and secondmolding members 20 and 30. The second synthetic resin, as shown in FIG.9, is fed to the retainer grooves 23 and 33 of the first and secondmolding members 20 and 30. At this time, the nozzle grooves 24 areinclined at a predetermined angle along a flow of the second syntheticresin introduced into the retainer grooves 23 and 33. Accordingly, thesecond synthetic resin is also fed to the nozzle grooves 24. Once thesecond synthetic resin is fully filled in the retainer grooves 23 and33, the second synthetic. resin moves to the whole surface of thesynthetic resin passages 21 and 31 through the space, which is formed bythe slit surface 32 and the lead surface 22, by the pressure of thesecond extruder. As a result, the synthetic resin moving through thewhole surface of the synthetic resin passages 21 and 31 is coated withthe second synthetic resin. At this time, since the second syntheticresin moves to the space formed by the nozzle grooves 24 and the slitsurface 32 at a greater amount, the wood pattern 1 a is formed on thesurface of the product 1. That is, as shown in FIG. 10, the wood patternla is formed on lower and upper surfaces of the product 1.

[0042] The second synthetic resin contains, a wood powder obtained bygrinding wood as described above. However, the second synthetic resinmay be formed of other materials as the case may be.

[0043] Furthermore, the retainer grooves 23 and 33 are formed tosurround the synthetic resin passages 21 and 31 so that the wholesurface of the synthetic resin is equally coated with the secondsynthetic resin. That is, at a portion close to the connecting passage40 supplied with the second synthetic resin, the retainer grooves 23 and33 are formed far away from the synthetic resin passages 21 and 31. Bycontrast, at a portion far away from the connecting passage 40, theretainer grooves 23 and 33 are formed close to the synthetic resinpassages 21 and 31. Also, it should be noted that the retainer grooves23 and 33 are bent depending on sectional shapes of the synthetic resinpassages 21 and 31.

[0044] Furthermore, even if a molding member is designed by consideringvarious cases, the second synthetic resin is introduced into thesynthetic resin passages 21 and 31 at different ratios depending onposition. In this case, some wood pattern may naturally be formed.However, in the present invention, since the nozzle grooves 24 areformed, accurate wood pattern can artificially be formed.

[0045] As described above, the extrusion molding apparatus for a producthaving a wood pattern and the extrusion molding method according to thepresent invention have the following advantages.

[0046] Since the product having a wood pattern is formed by the firstand second synthetic resins, the wood pattern is not taken off andesthetic appearance can be obtained.

[0047] In addition, the finished product is manufactured by one timeprocess, and no process of wrapping a sheet paper of a wood pattern isrequired. This reduces the process steps and thus enhances theproductivity.

[0048] The foregoing embodiments are merely exemplary and are not to beconstrued as limiting the present invention. The present teachings canbe readily applied to other types of apparatuses. The description of thepresent invention is intended to be illustrative, and not to limit thescope of the claims. Many alternatives, modifications, and variationswill be apparent to those skilled in the art.

What is claimed is:
 1. An extrusion molding apparatus for successivelyproducing a product having a wood pattern with a predetermined sectionalshape by feeding a thermoplastic synthetic resin to an extruder andextruding the product through a die installed at an outlet of theextruder, wherein a second inlet is formed at one side of the die to fita second synthetic resin thereinto, a second extruder which feeds thesecond synthetic resin is connected to the second inlet, and a secondpassage communicated with the second inlet of the die is formed tocommunicate with an original synthetic resin passage formed in the die,thereby coating. the second synthetic resin on a surface of the productextruded from the die.
 2. The extrusion molding apparatus of claim 1,wherein the second passage of the die is formed to communicate with theoriginal synthetic resin passage so that the whole surface of theproduct is coated with the second synthetic resin and a sectional areaof the second passage is irregularly formed, thereby forming the woodpattern.
 3. The extrusion molding apparatus of claim 1, wherein thesecond synthetic resin fed from the second extruder contains a woodpowder of 80˜120 meshes at a predetermined ratio.
 4. An extrusionmolding method for successively producing a product having a woodpattern with a predetermined sectional shape by feeding a thermoplasticsynthetic resin to an extruder and extruding the product through a dieinstalled at an outlet of the extruder, the extrusion molding methodcomprising the steps of: forming a second passage in a synthetic resinpassage formed in the die to communicate with the synthetic resinpassage; and connecting a second extruder to the second passage so thatthe second synthetic resin is coated on a surface of the product.
 5. Theextrusion molding method of claim 4, further comprising the step offorming the second passage to communicate with an original syntheticresin passage so that the whole surface of the product is coated withthe second synthetic resin.
 6. The extrusion molding method of claim 5,further comprising the step of irregularly forming a sectional area ofthe second passage so that the second synthetic resin is fed to eachportion of the product at different ratios, thereby forming a woodpattern by the second synthetic resin.
 7. The extrusion molding methodof claims 4, wherein the second synthetic resin contains a wood powderof 80˜120 meshes at a predetermined ratio.
 8. A product having a woodpattern characterized in that a second synthetic resin is formed on anouter surface of the product produced by extrusion molding, at differentratios depending on positions.
 9. The product having a wood pattern ofclaim 8, wherein the second synthetic resin contains a wood powder of80˜120 meshes at a predetermined ratio.
 10. An extrusion molding die fora product having a wood pattern, provided with a thermoplastic syntheticresin and a synthetic resin passage, the thermoplastic synthetic resinbeing installed at an outlet of an extruder so that it is to be fed tothe extruder and then extruded in the product having a predeterminedsectional shape such as the synthetic resin passage, the extrusionmolding die characterized in that a second inlet is formed at one sideof the die to fed a second synthetic resin thereto, and the second inletis formed to communicate with a second passage communicated with thesynthetic resin passage of the die so that the second synthetic resin iscoated on a surface of the product extruded from the die.
 11. Theextrusion molding die of claim 10, wherein the second passage is formedaround the second synthetic resin passage so that the whole surface ofthe product is coated with the second synthetic resin.
 12. The extrusionmolding die of claim 11, wherein the second passage is formed on thewhole surface of the product at a constant interval so that the secondsynthetic resin of a predetermined ratio passes through the wholesurface of the product.
 13. The extrusion molding die of claim 11,wherein the second passage includes a retainer communicated with thesecond inlet at the outmost so that the second synthetic resin isintroduced into the second passage at a constant pressure.
 14. Theextrusion molding die of claim 13, wherein the second passage includes anozzle passage which is greater than a sectional area of the secondpassage but smaller than a sectional area of the retainer, the nozzlehaving one end communicated with the retainer and the other endcommunicated with the synthetic resin passage.
 15. The extrusion moldingdie of claim 14, wherein the retainer and the nozzle passage have acurved section.
 16. The extrusion molding die of claim 14, wherein thenozzle passage has a sectional area which is gradually reduced towardthe synthetic resin passage.
 17. The extrusion molding die of claim 14,wherein the nozzle passage is inclined at a predetermined angle along aflow of the second synthetic resin.
 18. The extrusion molding die ofclaims 10, wherein the second synthetic resin contains a wood powder of80˜120 meshes at a predetermined ratio.